Atomic layer deposition head

ABSTRACT

An ALD coating method to provide a coating surface on a substrate is provided. The ALD coating method comprises: providing a deposition heading including a unit cell having a first precursor nozzle assembly and a second precursor nozzle assembly; emitting a first precursor from the first precursor nozzle assembly into chamber under atmospheric conditions in a direction substantially normal to the coating surface; emitting a second precursor from the first precursor nozzle assembly into chamber under atmospheric conditions in a direction substantially normal to the coating surface; removing moving the substrate under the deposition head such that the first precursor is directed onto a first area of the coating surface prior to the second precursor being directed onto the first area of the coating surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/584,034 filed on Dec. 29, 2014 which is a divisional of U.S. patentapplication Ser. No. 13/273,417, filed Oct. 14, 2011, which claimspriority under 35 U.S.C. 119(e) based upon each of ProvisionalApplication No. 61/455,223, filed Oct. 16, 2010, Provisional ApplicationNo. 61/455,772, filed Oct. 26, 2010, and Provisional Application No.61/466,885, filed Mar. 23, 2011, all of which are incorporated herein byreference in their entirety.

COPYRIGHT NOTICE

A portion of the disclosure of this patent document may contain materialthat is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent files or records, but otherwise reserves all copyrightrights whatsoever. The following notice shall apply to this document:Copyright 2011, Cambridge Nanotech, Inc.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to methods and apparatus for gasdeposition. More specifically the present invention relates to devicesand methods suitable for applying multiple thin film materials layersonto a moving substrate by atomic layer deposition (ALD) carried out atatmospheric pressure.

Description of the Related Art

Systems for coating moving substrates at atmospheric pressure using ALDcoating methods are known and disclosed in U.S. Pat. No. 7,413,982 byLevy et al. entitled PROCESS FOR ATOMIC LAYER DEPOSITION and relateddisclosures by Levy et al. Levy et al. disclose in FIGS. 2 and 5 a gasdistribution manifold having three gas inlet ports for receiving a firstprecursor gas, a second precursor gas and an inert gas therein. Thedistribution manifold is formed with an output face having a pluralityof output channels with first output channels emitting the firstprecursor gas out therefrom, second output channels emitting the secondprecursor gas out therefrom and third output channels, disposed betweeneach of first and second output channels, emitting the inert gas outtherefrom. The output face is disposed opposed to a substrate coatingsurface and is uniformly spaced apart from the substrate coating surfaceby a distance D such that each output channel is separated from thecoating surface by the distance D. The output channels are separated bypartitions which are shared by adjacent output channels. The partitionssubstantially confine gas flow to channels defined by opposingpartitions. Gas is delivered into each output channel is directedparallel to the substrate coating surface and is confined to flow in theoutput channel by the partitions and the substrate coating surface.

In operation, the distribution manifold and or substrate are movedrelative to one another. The direction of relative motion isperpendicular to the direction of gas flow in the output channels. Therelative motion sequentially advances each output channel over thecoating surface. Thus the coating surface is first exposed to the firstprecursor flowing through a first output channel. During the period thatthe coating surface is exposed to the first precursor the firstprecursor reacts with the substrate coating surface to alter the coatingsurface and produce a reaction byproduct. The coating surface is nextexposed to an inert gas flowing through an inert gas output channel. Asshown in Levy et al. FIGS. 7A and 7B the inert gas channel removesunreacted first precursor and reaction byproduct from the coatingsurface and carries the outflow to an exhaust port. The coating surfaceis next exposed to the second precursor gas flowing through a secondoutput channel. During the period that the coating surface is exposed tothe second precursor the second precursor reacts with the substratecoating surface and forms a thin film solid coating thereon and producesa reaction byproduct. The coating surface is next exposed to a secondinert gas flowing through an inert gas output channel which removesunreacted second precursor and reaction byproduct from the coatingsurface.

It is well know that mixed precursor gases readily react with each otherand most surfaces that they come into contact with and that mixedprecursors contaminate the surfaces by forming solid material layersthereon. When mixed precursors contaminate a substrate coating surfaceits physical and chemical properties can be compromised with very littlevisible sign that the surface is contaminated. In the case of thedistribution manifold disclosed by Levy et al., mixed precursors in theinert gas channels can contaminate surfaces of the distribution manifoldand other surfaces of the exhaust system, including pump valves andsensors that come into contact with the outflow. Surface contaminationresulting from contact with mixed precursor usually leads to performancedegradation and eventual failure.

One problem with the distribution manifold disclosed by Levy et al. isthat the separation distance D between the coating surface and theoutput face of the distribution manifold is necessary small. Inparticular, Levy et al. disclose that a separation D of approximately0.025 mm, or 25 μm is advantageous because it prevents precursor gasesfrom flowing around channel partitions between the distribution head andthe coating surface thereby preventing different precursors from mixingtogether, e.g. in the inert gas channels. Additionally Levy et al.discloses in FIGS. 8A and 8B that a small separation D advantageouslyreduces the reaction time of a precursor with the coating surface sincethe precursor reaches the coating surface more quickly. HoweverApplicants have found that the small separation distance D is notpractical in a typical coating application because many substratematerials being coated have, surface variations that exceed 25 μm; theseparation distance recommended in Levy et al. In particular variationsin substrate thickness, in the geometry of elements supporting thesubstrate and in the manifold itself can easily exceed 25 μm with theresult that during movement of the coating surface past the distributionmanifold at the desired coating velocity contact between the coatingsurface and the distribution manifold can easily occur resultingundesirable coating surface and substrate damage.

While Levy et al. argue that the small separation D is an improvementover the prior gas deposition system disclosed in U.S. Pat. No.6,821,563 to Yudovsky, entitled GAS DISTRIBUTION SYSTEM FOR CYCLICALLAYER DEPOSITION, the Yudovsky system uses a separation distance of 500μm or more which is a more practical separation for coating movingsurfaces.

Yudovsky discloses a cyclic layer deposition system in FIG. 1 thatincludes a sealed processing chamber maintained at less than atmosphericpressure during coating cycles. The system includes a gas distributionmanifold supported inside the process chamber in a fixed position. Thesystem includes a shuttle that supports a substrate being coated andtransports the substrate past the gas distribution manifold in a linermotion. The distribution manifold includes first gas ports connected toa first precursor supply for receiving a first precursor gas therein,second precursor ports connected to a second precursor gas supply forreceiving a second precursor gas therein, purge ports connected to aninert gas supply for receiving inert gas therein and vacuum portsconnected to a vacuum system for removing gas from the process chamber.The gas ports are arranged with each precursor port flanked by opposingpump ports and with a purge port disposed between opposing first andsecond precursor ports.

Each of the gas port is separated from adjacent gas ports by partitions.The partitions extend close to the substrate coating surface and isolategas flow from adjacent gas ports and direct gas flow toward the coatingsurface. Each gas port has an open end facing the coating surface suchthat gas exiting from gas ports impinges the coatings surface to eitherreact with the coating surface as is the case for the precursor gases orpurge precursors from the coating surface as the case for the inert gasexiting from the purge ports. A lower end of each partition is separatedfrom the coatings surface by a separation spacing of about 500 μm ormore to allow gas streams exiting from precursor ports to flow aroundthe lower end of the partitions toward the adjacent vacuum ports.

While the gas distribution manifold disclosed by Yudovsky provides amore practical separation distance between the lower end of eachpartition and the coating surface Yudovsky suffers from othershortcomings. In particular, Yudovsky requires that the process chamberbe sealed and the coating process be carried out in vacuum or at leastbelow atmospheric pressure. This complicates loading and unloading ofsubstrates which are transported between a load lock chamber and theprocess chamber at the beginning and end of each coating cycle and thissubstantially increases coating cycle times. Additionally Yudovskyrequires that the substrate be moved past the distribution manifold by areciprocating linear motion or that individual wafers be rotated pastthe gas distribution manifold a shown in FIGS. 3 and 5. This furtherincreases process cycle times by requiring two linear motion directionsin the case of the linear reciprocation and loading and unloading ofwafers in the case of rotary motion.

There is a need in the art to coat webs or rolls or webs of substratematerial with coatings that can be readily provided by existing ALDcoating chemistries. Moreover it is desirable to apply such coatings atatmospheric pressure in order to avoid the high cost and complexity ofcoating substrates in a vacuum chamber and to avoid increased cycletimes associated with loading substrates into and unloading substratesfrom a vacuum or sealed chamber. While Levy et al. disclose a system forALD coating at atmospheric pressure, the system disclosed by Levy et al.requires a small separation distance (25 μm or less) between thesubstrate coating surface and the lower ends of the partitions used toform gas flow channels and a 25 μm, separation distance is impracticalfor many applications that require more variability in the separationdistance. One problem is that the thickness of the some materials beingcoated can vary more than 25 μm. Another problem is that materialstretching and position variations due to transport drive forces cancause the separation distance to vary more than 25 μm as the material isadvanced past the gas distribution manifold. This is particularlyproblematic as web transport velocities reach 0.5 to 20 m/sec which is avelocity range enabled by systems and methods of the present invention.Accordingly there is a need in the art to provide systems and methodscapable of delivering reliable coating ALD properties with a substrateto gas manifold separation distance in the range or 500 μm to 3 mm ormore to accommodate variations in the separation distance due tovariable material thickness and dynamic changes in separation distancedue to material stretch and movement introduced by material transportmechanisms.

More generally, there is a need to increase ALD coating rates (e.g. asmeasured in square meters per minute). The present invention addressthis need by providing improved systems and method for ALD coating atatmospheric pressure thereby eliminating process chamber load and unloadcycle times and pump down and purge cayle time associated with sealchambers used in conventional ALD coating systems. Additionally, thepresent invention increases coating rates per minute by optimizing unitcell dimensions and gas volume delivery to the substrate that providecomplete saturation at desired substrate velocities.

Additionally there is a need to achieve faster saturation of substratesurfaces at increased substrate velocities. The present inventionaddresses this need by providing faster and more uniform process gasdelivery and removal over substrate areas exposed to individual gaschannels.

There is a further need to reduce the volume of chemistries used toachieve saturation of substrate surfaces being coated using ALDprocesses. The present invention addresses this need by reducing thevolume of chemistries used during a first exposure by optimizing unitcell dimensions and gas volume delivery to the substrate according todesired substrate transport velocities and by providing an opportunityto reuse unreacted precursors by segregating and collecting dissimilarprecursors removed during purge cycles. The reaction zone proximate tothe substrate surface.

SUMMARY OF THE INVENTION

Methods and apparatus for depositing a layer on a coating surface aredescribed herein.

In one aspect, a method of depositing a layer on a coating surface of asubstrate is provided. The method comprises providing a deposition headincluding a unit cell having a first precursor nozzle assembly and asecond precursor nozzle assembly; emitting a first precursor from thefirst precursor nozzle assembly into atmospheric conditions in adirection substantially normal to the coating surface; and, emitting asecond precursor from the second precursor nozzle assembly intoatmospheric conditions in a direction substantially normal to thecoating surface. The method further comprises relatively moving thedeposition head and the substrate such that the first precursor isdirected onto a first area of the coating surface prior to the secondprecursor being directed onto the first area of the coating surface.

In one aspect, a deposition system is provided. The system comprises asubstrate including a coating surface, and a deposition head including aunit cell having a first precursor nozzle assembly and a secondprecursor nozzle assembly. The first precursor nozzle assembly isconstructed and arranged to emit a first precursor into atmosphericconditions in a direction substantially normal to the coating surfaceand the second precursor nozzle assembly is constructed and arranged toemit a second precursor into atmospheric conditions in a directionsubstantially normal to the coating surface. The system furthercomprises an actuator associated with the deposition head and/or thesubstrate. The actuator is configured to generate relative motionbetween the deposition head and the substrate for exposing a first areaof the coating surface to the first precursor followed by exposing thefirst area of the coating surface to the second precursor.

In one aspect, a deposition head is provided. The deposition headcomprises a plurality of first precursor nozzle assemblies; a pluralityof second precursor nozzle assemblies; and, a plurality of inert gasnozzle assemblies respectively arranged between the first precursornozzle assemblies and the second precursor nozzle assemblies. Thedeposition head further comprises a plurality of first exhaust channelsarranged between the first precursor nozzle assemblies and the inert gasnozzle assemblies; and, a plurality of second exhaust channels arrangedbetween the second precursor nozzle assemblies and the inert gas nozzleassemblies. The deposition head further comprises a first precursordelivery system for delivering first precursor to each of the pluralityof first precursor nozzles; a second precursor delivery system fordelivering second precursor to each of the plurality of second precursornozzles; and, an inert gas delivery system for delivering inert gas toeach of the plurality of inert gas nozzles. The deposition head furthercomprises an exhaust gas removal system for drawing exhaust gas througheach of the first exhaust channels and each of the second exhaustchannels and removing the exhaust gas from deposition head.

These and other aspects and advantages will become apparent when theDescription below is read in conjunction with the accompanying Drawings.

BRIEF DESCRIPTION OF DRAWINGS

The features of the present invention will best be understood from adetailed description of the invention and a preferred embodiment thereofselected for the purposes of illustration and shown in the accompanyingdrawings in which:

FIG. 1 illustrates a schematic side section view of a unit cell suitablefor atmospheric ALD according to one example embodiment of the presentinvention.

FIG. 2 illustrates a schematic bottom view of a gas deposition systemthat includes a moving substrate and a stationary single unit cell gasdistribution manifold according to one example embodiment of the presentinvention.

FIG. 3 illustrates a schematic side section view of a gas depositionmanifold that includes four unit cells disposed over a moving substrateaccording to one example embodiment of the present invention.

FIG. 4 illustrates a schematic side section view of a single gas nozzleand associated spacers suitable for atmospheric ALD coating of a movingsubstrate according one example embodiment of the present invention.

FIG. 5 illustrates a graphical plot of dwell time in seconds vs.substrate linear velocity in meters per minute for three differentnozzle widths according to one aspect of the present invention.

FIG. 6 illustrates a graphical plot of channel width in millimeters vs.substrate velocity in meters per minute for three dwell times inmilliseconds according to one aspect of the present invention.

FIG. 7 illustrates an isometric view of a gas distribution manifoldsupported over a substrate linear transport mechanism suitable forperforming the ALD coating cycles according to one aspect of the presentinvention.

FIG. 8 illustrates an isometric view of the gas distribution manifoldaccording to the present invention.

FIG. 9 illustrates a cross-section in isometric view of a gasdistribution manifold according to the present invention.

FIG. 10 illustrates an isometric section view of a unit cell of aprecursor a precursor orifice plate according to an embodiment of thepresent invention.

FIG. 11 illustrates an isometric section view of a unit cell of aprecursor orifice plate according to another embodiment of the presentinvention

FIG. 12 illustrates an isometric section view of a gas distributionmanifold illustrating input gas flow according to one aspect of thepresent invention.

FIG. 13 illustrates an isometric section view of a unit cell of a gasdistribution manifold illustrating exhaust gas flow according to oneaspect of the present invention.

FIG. 14 illustrates a schematic diagram illustrating a gas controlsystem according to one aspect of the present invention.

FIG. 15 illustrates a schematic side section view of a deposition systemsuitable for atmospheric ALD including a moving substrate according toan embodiment of the present invention.

FIG. 16 illustrates a schematic side section view of a deposition systemsuitable for atmospheric ALD including a moving substrate according toan embodiment of the present invention.

CALLOUTS

100 Unit cell 1000 Unit cell 1^(st) embodiment 110 Coating surface 1005AFirst precursor nozzle assembly 120 1^(st) Precursor nozzle assembly1005B Second precursor nozzle assembly 130 2^(nd) precursor nozzleassembly 1010A Exhaust inlet 135 Velocity vector 1010B Exhaust inlet 140Substrate leading edge 1010C Exhaust inlet 150 1^(st) Purge nozzleassembly 1015A Purge nozzle assembly 160 2^(nd) Purge nozzle assembly1015B Purge nozzle assembly 170 Spacer 1025 Substrate 172 End spacer1030 Separation distance 175 Nozzle bottom edge 1100 Second Embodimentof the Gas Orifice Plate 180 Nozzle aperture 1105 Exhaust 185 Spacerbottom edge 1110 Precursor 1 Input 1115 Purge Gas Input 200 Unit cell1120 Precursor 2 Input 210 Substrate 1130 Substrate 220 1^(st) Precursornozzle 1140 1^(st) separation distance 230 2^(nd) Precursor nozzle 11453^(rd) separation distance 250 1^(st) Purge nozzle 1150 Base wallsurface 260 2^(nd) Purge nozzle 1155 Vertical walls 265 Exhaust element1160A Base wall 280 Exhaust channel 1160B Base wall 285 Exhaust channel1162 Protruding wall 290 Flow channel 1165 Base wall 292 Nozzle aperture1170 Gas orifice 295 Exhaust conduits 1175 2^(nd) separation distance300 Disposition head system 1235A Longitudinal Slot 310 Unit cell 1235BLongitudinal Slot 320 Unit cell 1237 Traverse Feed Slot 330 Unit cell1240 Longitudinal Feed Slot 340 Unit cell 1241 Longitudinal Feed Slot360 1^(st) Precursor supply system 1242 Longitudinal Feed Slot 3702^(nd) Precursor supply system 1300 Exploded unit cell 372 End spacer1305 Central wall 380 Inert gas supply system 1310 Longitudinal slot 390End channel 1315 Longitudinal slot 1320 Orifice 400 Single nozzleassembly 1325 Orifice 410 Nozzle 1330 Longitudinal input slot 420 Spacer1335 Precursor nozzle assembly 430 Spacer 1340 Precursor nozzle assembly1345 Base wall 500 Insert 1350 Purge nozzle assembly 1355 Exhaust inlet700 ALD Coating System 1355A Alternate exhaust inlet 705 Access Hatch1370 Orifice 710 Gas Manifold 1375 Side walls 715 Removable Lid 1400 Gascontrol system 720 Various Access Ports 1405 Inert gas supply 725 LinearBellows 1410 Pressure regulator 730 Motor Drive 1412 Input conduit 735Linear Track 1420 Pressure regulator 740 Ball Screw Assembly 1425 Massflow controller 745 ALD chamber enclosure 1435 Valve 1440 Valve 805Precursor A Exhaust 1445 Valve 810 Precursor B Exhaust 1450 Bubblers 815Precursor A Input 1455 Mass flow controller 820 Precursor B Input 1460Gas manifold 825 Purge Gas Input 1465 Precursor exhaust line 830 ExhaustCollection Manifold B 1470 Precursor exhaust line 835 Exhaust CollectionManifold A 1475 Exhaust gas collection module 1480 Throttle Valve 900Cross-section of Gas Manifold 1485 Blower 910 Exhaust gas A 915 ExhaustCollection Plate 1500 Deposition System 920 Exhaust Orifice Plate 1510Unit Cell 925 Flow Distribution Plate 1520 Unit Cell 930 PrecursorOrifice Plate 1530 Unit Cell 1540 Unit Cell 1035 Opposing Side Walls1550 Supply Roll 1040 Hollow Chamber 1560 Take-up Roll 1045 Base Wall1570 Substrate Support 1050 Bottom surface 1580 Drive Mechanism 1055Hollow Chamber 1585 Gas Supply Module 1060 Longitudinal Slot Opening1590 Exhaust Module 1070 Precursor orifices 1600 Deposition System DSeparation distance 1610 Unit Cell G Film thickness growth 1620 UnitCell L Unit cell longitudinal length 1630 Unit Cell Tc Cycle time 1640Unit Cell Td Dwell time 1650 Supply Roll Tm Material layer thickness1660 Take-Up Roll V Velocity 1670 Substrate Support W Nozzle width 1680Drive Mechanism Wc Unit cell width Wd Deposition head width Ws Substratewidth

DESCRIPTION OF SOME EMBODIMENTS OF THE INVENTION

Referring to FIGS. 1 and 2, a schematic section view of a unit cell(100), which forms a portion of a gas deposition head that preferablyincludes a plurality of unit cells. The unit cell is shown disposedabove a solid substrate which includes a top surface or coating surface(110) which is the surface that is being coated by the unit cell (100).In the example embodiments described below the gas deposition process isatomic layer deposition, (ALD) process; however, the apparatus andmethods disclosed herein can be used as is or adapted to perform othergas deposition processes such as forming a thin film coating onto thecoating surface by directing a single gas or vapor precursor onto to thecoating surface or such as forming a thin film coating onto the coatingssurface by sequentially directing more than two dissimilar precursorsonto the coating surface or such as forming a thin film coating bydirecting a mixture of two or more dissimilar gas or vapor precursoronto to the same region of the coating surface simultaneously.

The substrate may comprise any material suitable for being coated by anALD process or by other gas and vapor deposition processes. Somenon-limiting example substrate include metals, ceramics, plastics,semiconductors, dielectrics, woven fabrics, and organic materials suchas wood, paper, and the like. The substrate may comprise a continuousweb of solid material or one or more discrete elements. Preferably theunit cell (100) is stationary and the substrate is moved past the unitcell at a velocity (V); however the unit cell may be moved relative to astationary substrate or substrates or both the substrate and unit cellmay be moved.

The unit cell (100) has a width (Wc) and a longitudinal length (L) andthe substrate has a width (Ws), both shown in FIG. 2. Preferably, theunit cell longitudinal length (L) substantially matches or exceeds thesubstrate width (Ws); however it may be desirable that the unit celllongitudinal length (L) is less than the substrate width (Ws) in somecoating applications. The unit cell (100) and the coating surface (110)are disposed substantially parallel with each other at least over thewidth (Wc) of the unit cell and are separated by a separation distance(D).

The unit cell (100) includes a first precursor nozzle assembly (120)configured to direct a first gas precursor onto the coating surface(110). The unit cell (100) further includes a second precursor nozzleassembly (130) configured to direct a second gas precursor onto thesurface (110). Preferably each of the first and second precursor nozzleassemblies (120, 130) is configured to direct precursor gassubstantially normal to the surface (110) across the entire substratewidth (Ws). Moreover it is preferable that each of the first and secondprecursor nozzle assemblies (120, 130) is configured direct asubstantially uniform volume of precursor gas onto the surface (110)across the entire width (Ws).

Referring now to FIGS. 1-3, in a preferred embodiment, a unit cell isconfigured to operate using an ALD coating cycle. In operation, thecoating surface (110) is advanced past the unit cell (100) at a velocity(V) in the direction indicated by the velocity vector (135) such that asubstrate leading edge (140) advances past the first precursor nozzleassembly (120) before advancing past the second precursor nozzleassembly (130). Thus the coating surface leading edge (140) is firstexposed to the first precursor exiting from the first precursor nozzleassembly (120) and thereafter exposed to the second precursor exitingfrom the second precursor nozzle assembly (130). The first and secondprecursor nozzle assemblies (120) and (130) each deliver a substantiallycontinuous flow of precursor gas. As will be recognized by those skilledin the art, in an ALD reaction the first precursor reacts with thecoating surface (110) and chemically alters the coating surface (110)prior to the coating surface (110) being exposed to the second precursorexiting from the second precursor nozzle (130). The chemically alteredcoating surface then reacts with the second precursor and the reactionwith the second precursor forms a first solid material layer or thinfilm onto the coating surface (110). Thus the preferred unit cell (100)includes two precursor sources each disposed over a different area ofthe coating surface (110) such that the coating surface is sequentiallyexposed to the first precursor followed by being exposed to the secondprecursor and the two working in combination deposit a single solidmaterial layer onto the coating surface (110) as the coating surface(110) is advanced past the unit cell. Alternately any combination ofrelative motion between the unit cell (100) and the coating surface(110) that advances the surface (110) first past the first precursornozzle assembly (120) and then past the second precursor nozzle assembly(130) can be used to deposit the single solid material layer on thesurface (110).

The unit cell (110) further includes a first inert gas or other suitablepurge nozzle assembly (150) disposed between the first and secondprecursor nozzle assemblies (120) and (130) and a second inert gas orpurge nozzle assembly (160) disposed adjacent to the second precursornozzle assembly (130), e.g. between the second precursor nozzle assembly(130) and a first precursor nozzle assembly of an adjacent unit celle.g. as shown in FIG. 3. Preferably each of the first and second purgenozzle assemblies (150, 160) is configured to direct inert gassubstantially normal to the coating surface (110) across the entiresubstrate width (Ws). Moreover it is preferable that each of the firstand second purge nozzle assemblies (150, 160) is configured to direct asubstantially uniform volume of precursor gas onto the surface (110)across the entire width (Ws). Additionally it is preferred that thepressure and volume of inert gas delivered onto coating surface (110) byeach of the purge nozzle assemblies (150, 160) exceed the pressure andvolume of precursor delivered to the coating surface (110) by each ofthe precursor nozzle assemblies (120, 130) such that the inert gasdirected onto the coating surface tends confine precursor gas flowproximate to the coating surface to the region between adjacent purgenozzle assemblies (150, 160).

The inert gas directed onto the surface (110) by the inert gas nozzleassemblies serves two purposes. The first purpose is to form an inertgas buffer zone disposed between the first and second precursorsproximate to the coating surface (110). The inert gas buffer zonesubstantially confines precursor gas proximate to the coating surface(110) to a longitudinal zone disposed along the entire longitudinaldimension (L) of the unit cell (100) thereby providing an inert gasbuffer zone that prevents the first and second precursors from mixingproximate to the coating surface (110). Additionally, the continuousflow of inert gas being directed onto the coating surface (110) by thepurge nozzle assemblies (150, 160) serves to continuously purgeunreacted precursor and reaction byproducts generated by the reactionsbetween the first and second precursors and the coating surface (110).More specifically, the leading edge (140) passes the first precursornozzle assembly (120) which exposes the leading edge to first precursorresulting in a chemical reaction between the first precursor and thecoating surface (110) and immediately thereafter the leading edge (140)passes the first inert gas nozzle assembly (150), which purges anyreaction byproducts and or unreacted first precursor from the leadingedge (140) before the leading edge (140) reaches the second precursornozzle assembly (130). Similarly, the leading edge (140) passes thesecond precursor nozzle assembly (130) which causes a chemical reactionbetween the second precursor and the coating surface (110) andimmediately thereafter the leading edge (140) passes the second inertgas nozzle assembly (160), which purges any reaction byproducts and orunreacted second precursor from the leading edge (140) before theleading edge (140) reaches the end of the unit cell. Thus the unit cell(100) operates as a continuous ALD material layer forming device thatsimultaneously directs the first precursor onto the coating surface(110), while continuously purging any unreacted first precursor andreaction byproducts from the coating surface (110) with the first inertgas nozzle assembly (150), while simultaneously directing the secondprecursor onto the coating surface (110) and continuously purging anyunreacted first precursor and byproducts from the coating surface (110)with the second inert gas nozzle assembly (160). Preferably, the unitcell (100) and coating surface (110) are substantially at atmosphericpressure in order to avoid the expense, complexity and throughputreductions associated with performing ALD processes in a vacuum chamber.Moreover, the process of simultaneously applying first and secondprecursors while simultaneously purging reaction byproducts fromdifferent regions of the coating surface as the coating surface (110)advances past the unit cell reduces coating cycle times as compared toALD processes carried out in a reaction chamber maintained at a vacuumpressure or low pressure that requires sealing the chamber duringcoating cycles since according to the present invention the precursorapplications and purging cycles are carried out simultaneously insteadof sequentially as is generally the case in a reaction chamber.

The unit cell (100) includes spacers (170) or is formed with integralspacing separating the nozzle assemblies (120, 150, 130, and 160) andfurther includes an end spacer (172) for spacing adjacent unit cellsapart from each other. Each nozzle assembly comprising interconnectedelements or a unitary plate or bar structure that include a nozzlebottom edge (175) and one or more nozzle apertures (180) for emittinggasses out therefrom. Generally each nozzle aperture is in fluidcommunication with a gas source and a gas feed system forces anappropriate gas or vapor to be expelled through the nozzle aperture anddirected onto the coating surface. The nozzle assemblies each furtherinclude spacer(s) (170) which may comprise walls or partitions disposedbetween adjacent nozzle apertures (such as 120 and 150). In thelongitudinal axis as shown in FIG. 2, each nozzle assembly comprises arow of nozzle apertures and each spacers comprises a sold wall orpartition that extends continuously along the entire longitudinal length(L) of the unit cell (100). In some embodiments the nozzle aperture(s)may be substantially coplanar with the spacer bottom edge (175) such asis shown in FIG. 10, or the nozzle apertures (120, 150, 130, 160) may berecessed from the bottom edge (175) e.g. shown in FIG. 11, such that thespacers or separators form longitudinal flow channels (290) that confinegas flow exiting from the row of nozzles apertures to a volume definedby corresponding longitudinal flow channel (290) formed by the spacersor separators. The spacer bottom edges (175) are spaced away from thecoating surface (110) by a separation distance (D), which may range fromsubstantially zero to about 5 mm but which is preferably between 0.5 and3 mm. In the example of FIG. 1, each nozzle assembly (120, 150, 130, and160) and each spacer (170, 172) has the same width dimension (w). Inother embodiments, the width dimensions of nozzles and spacers may benon-uniform and may be varied in a manner that produces desired gas flowpatterns.

Referring now to FIG. 2, a unit cell (200) and substrate (210) are shownin a bottom view. The unit cell (200) has a cell width (Wc) extendingsubstantially along the axis of the substrate velocity vector (V). Theunit cell (200) has a longitudinal cell length (L) that is substantiallyperpendicular to the cell width (Wc). The substrate (210) may comprise amaterial web having a substantially unlimited length along the velocityaxis (V) or the substrate (210) may comprise a plurality of discreetsubstrates supported on a transport surface such as a moving webconfigured to transport a plurality of discreet substrates supportedthereon past the unit cell (200) at a velocity (V). The substrate (210)has a substrate width (Ws). Preferably, the unit cell length (L) matchesor exceeds the substrate width (Ws). However the cell length (L) vs.substrate width (Ws) may be adapted according to particular coatingapplications including coating less than the entire width (Ws) of thesubstrate.

The unit cell (200) includes a plurality of nozzle assemblies includinga first precursor nozzle assembly (220), a second precursor nozzleassembly (230) and two inert gas or purge nozzle assemblies (250) and(260). As described above, a plurality of spacers or separators (170,172) are disposed between the nozzle assemblies to separate the nozzleassemblies from one another and in some cases (as shown in FIG. 11) todefine longitudinal gas flow channels (290) extending along the celllength (L). Each gas flow channel (290) may also fluidly interconnectwith one or more exhaust channels or plenums (280) and (285). In theexample embodiment, the exhaust channels or plenums (280, 285) aredisposed at opposing ends of each of the flow channels (290) extendingalong the velocity axis and one or both exhaust channels (280, 285) isin fluid communication with a volume that extends between the unit celland the coating surface defined by the separation distance (D). Theexhaust channels are also in fluid communication with an exhaust element(265), such as a vacuum pump or fan, via exhaust conduits (295). Theexhaust element (265) operates continuously to remove gas from theexhaust channels (280, 285) such that gas is continuously removed fromthe volume that extends between the unit cell and the coating surfacedefined by the separation distance (D). In the case when the unit cell(200) comprises a substantially planar bottom surface, e.g. when thenozzle apertures are flush with the spacer bottom edges (175), theseparation distance (D) is substantially uniform over the entireprocesses area and the exhaust channels (280, 285) may be positioned andconfigured to remove gas substantially uniformly along the entire unitcell width (Wc). In other cases where the nozzle apertures are recessedfrom the spacer bottom edges, the separation distance (D) is notuniform, the exhaust channels may be positioned and configured to removegas substantially from each of the longitudinal flow channels (290). Ineither case, the exhaust element (265) operates continuously to removegas from the exhaust channels (280, 285). In addition, the exhaustchannels (280, 285) of the unit cell (200) may be configured to fluidlycommunicate with the exhaust channels of adjacent unit cells whenseveral unit cells are assembled together to form a deposition head suchas the deposition head system (300) shown in FIG. 3.

In a further embodiment of the unit cell (200) gas flow in the purgenozzle assemblies (250, 260) is directed along the longitudinal axis (L)or parallel to the coating surface (110) instead of directed onto thecoating surface with normal incidence as described above. In thisembodiment of the unit cell (200) purge gas flows parallel to thecoating surface and sweeps any unreacted precursor and reactionbyproduct from the coating surface toward one or both of the exhaustchannels (280) and (285). The outflow from the exhaust channels is thencarried to the exhaust element (265) and vented or otherwise processed.In this embodiment, only the purge nozzle assemblies (220) and (230) arein fluid communication with the exhaust channels (280) and (285) suchthat gas flow in the precursor nozzle assemblies (220) and (230) doesnot enter the exhaust channels (280) and (285) but is instead drawntoward the purge nozzle assemblies and swept to the exhaust channels bythe longitudinal flow in each purge nozzle assembly. It is also notedthat the gas flow in alternating purge nozzle assemblies may be in samedirection or in opposite direction or the purge gas may enter each purgenozzle assembly at the center of the longitudinal axis and flow inopposite directs from the center to each of the opposing exhaustchannels (280) and (285).

As further shown in FIG. 2, each nozzle assembly (220, 250, 230, and260) includes a plurality of nozzle aperture (292) through which gas isexpelled under pressure. The nozzle assembly may comprise a plurality ofclosely spaced circular holes or other aperture shapes or one or morelongitudinal slots disposed along the longitudinal length (L) with eachcircular hole or slot in fluid communication with an appropriate feedplenum. In either case appropriate gases or vapors are directed onto thecoating surface substantially along the entire longitudinal length (L)and the number of and shape of the nozzle apertures are optimized toprovide a substantially uniform gas volume being expelled out of eachnozzle aperture (292). Thus the coating surface is simultaneouslyexposed to a substantially uniform volume of process or inert gas alongits entire longitudinal length (L) to promote uniform coating over thesubstrate width (Ws). Preferably each nozzle assembly (220, 250, 230,and 260) emits a substantially continuous flow of gas and each of theexhaust channels operates continuously to withdraw a substantiallycontinuous flow of gas from the volume between the unit cell and thesubstrate or from the purge nozzle assemblies as may be the case.

Referring now to FIG. 3 a non-limiting embodiment of a gas depositionhead system (300) includes four unit cells (310, 320, 330, 340)assembled together in an area array with each unit cell positioned at adistance (D) above a substrate coating surface (110). Each unit cell(310, 320, 330, and 340) is configured sustainably as shown in FIG. 1except only the end unit cell (340) includes an end spacer (372) forforming an end channel (390). Each unit cell (310, 320, 330, and 340)receives a supply of the first precursor gas from a first precursorsupply system (360) and delivers a volume of first precursor to each offour first precursor nozzle assemblies. Similarly a second precursorsupply assembly (370) delivers a volume of second precursor to each offour second precursor nozzle assemblies and an inert gas supply system(380) delivers a volume of inert gas to each of eight purge gas nozzleassemblies. Each gas supply system (360, 370, 380) may include a gassupply container (1, i, 2), a gas flow regulator, not shown, forregulating gas pressure and or mass flow rate and heating elements, notshown, for heating the precursors to a desired reaction temperature.Additionally, the system (300) may include a substrate transport system,not shown, an electronic controller, not shown, and various sensor andfeedback circuits, not shown, for sensing and controlling temperature,gas pressure and mass flow rate, substrate transport velocity, thin filmcoating thickness, and other properties as may be required.

The example deposition head system (300) includes four unit cells (310,320, 330, and 340) assembled together with unit cell widths (Wc)extending along the velocity axis such that the example head system(300) is configured to deposit four material layers onto the substratesurface (110) during one pass of the substrate over the assemble width(Wd). In the example embodiment (300), all four material layers beingdeposited onto the substrate surface (110) are substantially identicalmaterial layers with the composition and thickness of each materiallayer being substantially uniform and dependent on the composition ofthe first and second precursors applied to the coating surface (110).Ideally, the precursors and the coating surface (110) are maintained ata reaction temperature suitable for the desired reaction and thereaction temperature may range from 20.degree. C. to 600.degree. C.depending upon the precursor and substrate materials. In other exampleembodiments, one or more of the unit cells may be fed by a differentcombination of precursors such that the deposition head system (300) maybe configured to coat the coating surface (110) with solid materiallayers having different material compositions and or materialthicknesses without deviating from the present invention. In furtherexample embodiments, one or more of the precursor nozzle assemblies mayinclude plasma or other high energy sources suitable for ionizingparticles of a gas precursor.

Referring now to FIG. 4, a single nozzle assembly (400) includes anozzle assembly (410) and its surrounding spacers (420) and (430). Thenozzle assembly (400) may comprise any gas nozzle assembly of the unitcell (100). In the example embodiment of the nozzle assembly (400), thenozzle aperture area (410) and each of the spacers (420, 430) have thesame width (w); however other configurations are usable withoutdeviating from the present invention. When the coating surface (110)advances past the nozzle assembly (410) at a velocity (V) the timeduration that a portion of the coating surface (110) is passing under anozzle is called a Dwell Time (td) is given by:Dwell Time td=2w/V  [1]

Ideally, the dwell time is equal to the duration required for completesaturation of the area of the substrate surface that passes the nozzleduring the dwell time. More specifically complete saturation occurs whensubstantially every molecule of the coating surface that is available toreact with a molecule of the precursor completes a reaction. Thus anideal velocity (V) is one that if increased would cause less thancomplete saturation of the area of the substrate surface that passes thenozzle assemble width (2 w) during the dwell time. Other variables thatinfluence the level of saturation include the nozzle width w, the volumeof precursor that is available to react with the coating surface (110),the precursor and substrate temperature, the precursor pressure, gasturbulence proximate to the coating surface and the precursor gasconcentration in the region proximate to the coating surface. Similarlyit is preferred that each precursor nozzle assembly (410) and associatedspacers (420) and (430) are configured to provide substantially uniformprecursor availability and reaction conditions proximate to thesubstrate surface (110) across the entire unit cell longitudinal length(L) to ensure that complete saturation occurs over the entire substratewidth (Ws).

Referring now to FIG. 1, in one non-limiting example embodiment, a unitcell (100) includes a plurality of equal width precursor nozzleassemblies (120) and (130), purge nozzle assemblies (150) and (160) andequal width spacers (170, 172) and a substrate coating surface (110)advancing past the unit cell (100) at a velocity (V). Using the DwellTime of equation 1, the Cycle Time (t_(c)) required for the unit cell(100) to perform a single ALD cycle, i.e. to deposit a single materiallayer on to the surface (110) is given as:Cycle Time t _(c) =t _(prec1) +t _(purge) +t _(prec 2) +t_(purge)=8w/V  [2]

In the example embodiment shown in FIG. 3 wherein a plurality of unitcells is assembled together, the width (Wd) of the deposition head (300)is the combined width of (N) unit cells (100) and is given by:Deposition head width Wd=N(8w)  [3]

With each unit cell (310, 320, 330, 340) contributing a film thicknessgrowth (G), the total material layer thickness (Tm) applied by adeposition head of width (Wd), is given by:Material layer thickness Tm=NG=(Wc/8w)G  [4]Dwell Time and Substrate Velocity

Referring now to FIG. 5, characteristic times and dimensions associatedwith depositing films using the deposition head system (300) are showngraphically. Specifically FIG. 5 plots Dwell Time (td) in seconds as afunction of the substrate velocity for 3 different channel widths (w)ranging from 0.7-1.5 mm. As further shown in the insert (500) equations2-4 above indicate the ability to obtain material coating speeds of 24m/min for a dwell time of 5 ms corresponding to a 1 mm channel width.

Example 1

To understand key aspects of the dwell time more clearly, it isinstructive to consider the traditional deposition of an ALD film suchas Al.sub.2O.sub.3. Deposition of Al.sub.2O.sub.3 begins with the use ofa first precursor comprising Trimethylaluminum (TMA) and a secondprecursor comprising water (H.sub.2O). In a traditional ALD vacuumreactor, such as the SAVANNAH ALD system available from CambridgeNanotech Inc. of Cambridge Mass. based on previous deposition researchexperience we have estimated that a dwell time of 0.5 ms underatmospheric conditions will replicate the conditions seen for simplesaturation of the precursor on the substrate under vacuum conditions.Therefore dwell times of the precursor of 5 msec under atmosphericconditions (which is a factor of 100.times. greater than required forsimple saturation), should provide sufficient saturation even at speedsin excess of 20 m/min.

Channel Width and Substrate Velocity

Referring now to FIG. 6, the relationship between channel width andsubstrate velocity is shown graphically. Specifically FIG. 6 plotschannel width (w) vs. substrate velocity (V) for various dwell times(td). The plot generally shows that larger channel widths allow forgreater substrate velocities at more relaxed dwell times, however,larger channel widths can lead to impractical sizes for the depositionheads especially when a large total film thicknesses (i.e. a largenumber of unit cells) is required. However the plot further shows thatthe use of shorter dwell times allows the channel width to be reduced.

More specifically, FIG. 6 plots channel width (w) vs. substrate velocity(V) for three dwell times (td) of 5.0, 2.5, and 0.5 ms. Each curvedescribes the change in channel width required to maintain a fixed dwelltime as the substrate velocity increases. The results indicate that toachieve processing speeds on the order of 20 msec, the channel widthneeds to be maintained at approximately 1 mm, so that practical fullcell sizes can be maintained for thicker films.

More specifically one non-limiting embodiment of the present inventioncomprises a deposition system (300) constructed to operate with a dwelltime ranging from 0.1-5 ms, a 0.1-10 mm channel width and a substratevelocity ranging from 0.5 to 20 msec.

Example Gas Manifold and Linear Transport Device

Referring to FIG. 7, a non-limiting example ALD coating system (700)comprises a gas manifold (710) fixedly attached to an ALD chamberenclosure (745) and associated linear transport elements. The enclosure(745) includes a linear displacement mechanism housed therein with driveelements extending out therefrom. The linear displacement mechanism isconfigured to support a substrate or substrates being coated on thelinear displacement mechanism which transports the substrates(s) passedthe fixed gas manifold (710). The ALD chamber enclosure (745) isconfigured to load the substrate(s) being coated onto the lineardisplacement mechanism through an access hatch (705), which providesaccess into the ALD chamber (745).

The gas manifold (710) is adapted to deliver ALD precursors into the ALDchamber and to direct the ALD precursors onto a coating surface ofvarious substrate(s) as the substrate(s) are transported past the gasmanifold (710). The gas manifold (710) is further adapted to isolateprecursors from each other at the coating surface using inert gasseparation zones, described above, to purge unreacted precursor gasesand reaction byproduct away from the coating surfaces, and to exhaustthe unused precursor gases, reaction byproduct and inert gas to anexhaust area external to the gas manifold (710) and ALD chamberenclosure (745).

The chamber enclosure (745) is formed with various access ports (720)passing through side walls of the chamber enclosure (745). The accessports include gas and electrical fittings and connectors and the like toconnect gas input and output conduits to the access ports (720), and toconnect gauges, sensors, control devices, heaters, or other electricaldevices to the access ports for use inside the ALD chamber as may berequired. The top of the ALD chamber may have a removable lid (715).Preferably the ALD chamber is maintained substantially at atmosphericpressure and may be vented to atmosphere by a vent port, fan or thelike. Alternately the ALD chamber may be slightly pressurized, e.g. 1.1times atmospheric pressure, by pumping an inert gas flow into the ALDchamber enclosure (745) through an access port (720) such that gassesinside the ALD chamber tend to exit the ALD chamber through exitconduits provided in the gas manifold (710).

In the present non-limiting example embodiment, the linear displacementmechanism comprises a mechanical linear displacement system comprising aball screw assembly (740), linear track (735), motor drive or drivecoupling (730), and linear bellows (725), and the transport direction isalong the longitudinal axis of the linear bellows (725). While such asystem is convenient for evaluating the performance of the ALD coatingsystem (700), in further embodiments, the gas manifold (710) may bedisposed over a conveyer system, e.g. a conveyer belt, or the like, thatcontinuously advances a plurality of discrete substrates supported on aconveyer belt past the gas manifold (710). As with the system (700), thecontinuous web transports substrates past the manifold (710) along atransport axis substantially defined by the longitudinal axis of thelinear bellows (725). In a further embodiments, the gas manifold (710)may be disposed over a web of substrate material that is transportedpast the gas manifold such that the entire web of material is coatedwith one or more thin film layers as precursors exiting from the gasmanifold react with a coating surface of the web of substrate material.

In addition, ALD coating system (100) interfaces with an electroniccontroller, not shown, which at least includes a precision lineartransport drive system and linear position feedback system for operatingthe motor drive (730), or the like, at various speeds to maintain one ormore substantially constant linear velocities of the substrate beingcoated as it passes the gas manifold (710). Additionally, the electroniccontroller interfaces with elements of a gas flow control system shownin FIG. 7 and various other electric elements associated with operatingand evaluating the performance of the system (700).

Example Gas Manifolds

Referring to FIGS. 7-14, a non-limiting example gas manifold (710)according to the present invention is configured to direct precursor gasflows onto substrate coating surface(s) as the coating surface(s)advance past a precursor orifice plate (930). Additionally gas manifold(710) is configured to direct inert gas flows onto the coatingsurface(s) between precursor gas flows in a manner that preventsdissimilar precursors from mixing. Furthermore gas manifold (710) isconfigured to draw gas flows away from coating surface(s) and removeexhaust gases from the gas manifold (710). As depicted in FIG. 8 the gasmanifold (710) includes a plurality of input ports for receivingdifferent precursors therein. One or more input ports (815) receive asupply of a first gas or vapor precursor A from a first precursor sourceand one or more input ports (820) receive a supply of a second gas orvapor precursor B from a second precursor source. In addition, the gasmanifold (710) includes one or more input conduits (825) each in fluidcommunication with an inert gas source such as a nitrogen based gas,neon gas, argon gas, xenon gas, helium gas or a combination thereof. Inaddition, the gas manifold (710) includes one or more output or exhaustconduits (805, 810) which may be connected to one or more outflowdepositories for collecting and in some embodiments processing theexhaust gases.

As best viewed in FIGS. 9-14 exhaust gases are collected from thecoating surface(s) through a plurality of exhaust inlets (1010A, 1010B,1105A, 1105B) passing through the precursor orifice plate (930). Exhaustgasses collected by exhaust inlets are conveyed to the exhaustcollection manifolds (830) and (835) by exhaust flow channels thatextend from the exhaust inlets through each of the plates (925), (920)and (915). The exhaust gases comprise a mixture of unreacted precursor,reaction byproduct and inert gas. In a preferred embodiment, exhaustgases are segregated according to which unreacted precursor theycontain. More specifically, according to one aspect of the presentinvention, the gas manifold (710) is configured to exhaust gasses thatcontain unreacted precursor A and unreacted precursor B in separatesegregated exhaust flow channels. First exhaust flow channels arearranged to convey exhaust gasses that contain unreacted precursor A toa first exhaust collection manifold (835) which includes an exhaust port(805). Similarly second exhaust flow channels are arranged to conveyexhaust gasses that contain unreacted precursor B to a second exhaustcollection manifold (830) which includes an exhaust port (810). Each ofthe exhaust ports (805) and (810) are in fluid communication with ablower (1485) which operates to draw the exhaust gases out of theexhaust ports (805) and (810) and deliver exhaust gases removed from thegas manifold to an exhaust gas collection module (1475). Preferably,exhaust gas collection module (1475) comprises two separate chambers orchannels for collecting and segregating the outflow from the exhaustport (805) from the outflow from the exhaust port (810) so the eachoutflow can be further processed to separately reclaim unreactedprecursors A and B for reuse. In various embodiments a single blower(1485) may be used to draw exhaust gas out of both exhaust collectionmanifolds (835) and (830) or each exhaust collection manifold may be influid communication with a separate blower (1485). In furtherembodiments, the gas manifold (710) may be configured to combine theentire exhaust gas outflow into a single exhaust manifold e.g. bycombining the exhaust manifolds (830) are (835) into a single exhaustmanifold. In addition to removing exhaust gases from one or both of theexhaust gas manifolds (830) and (835) the blower or blowers (1475)operate to lower gas pressure in each of the exhaust gas manifolds whichacts to draw gas away from the coating surface through the plurality ofexhaust inlets (1010A, 1010B, 1105A, 1105B) passing through theprecursor orifice plate (930). By comparison with the unit cell (100)shown in FIG. 1, the exhaust inlets (1010A, 1010B, 1105A, 1105B) aredisposed in the locations of the spacers (170, 172).

As best viewed in FIGS. 9-13, process gases enter and flow through thegas manifold (710) as follows. Precursor A enters through one or moreprecursor A input ports (815), and is conveyed to the substrate coatingsurface through first precursor flow channels that are dedicated toconveying precursor A exclusively. Similarly Precursor B enters throughone or more precursor B input ports (820) and is conveyed to thesubstrate coating surface through second precursor flow channels thatare dedicated to conveying precursor B exclusively. Similarly purge gasenters through one or more purge gas input ports (825) and is conveyedto the substrate coating surface through purge gas flow channels thatare dedicated to conveying purge gas exclusively. Each of the first andsecond precursor channels and the purge gas channel pass through theprecursor orifice plate (930) and through each of the plates (925),(920) and (915).

A bottom face of the gas manifold (710) is formed by the precursororifice plate (930). The bottom face is preferably square or rectangularhaving a longitudinal dimension (Lh) extending along the longitudinalaxis (L) and a transverse dimension (Wc) extending substantiallyperpendicular to the longitudinal dimension (Lh) along the velocity axis(V) which is the axis defined by the substrate velocity. In variousembodiments the precursor orifice place (930) may be configured to applygas deposition layers over a process area having a longitudinaldimension ranging from 4 to 36 inches and a transverse dimension rangingfrom 0.2 to 36 inches. The skilled artisan will recognize otherfunctioning dimensions and shapes for the precursor orifice plate's(930) bottom face and process area are included in the scope of thepresent invention. More generally, the gas manifold (710) is configuredwith its longitudinal dimension (Lh) matched to or exceeding a widthdimension (Ws) of a substrate coating surface and with its transversedimension or head width (Wc) corresponding with the number of unit cellscontained in the gas manifold (710), e.g. as set forth in equation 3above. As noted above, the head width (Wc) comprises some multiple ofwidth of a single unit cell, (e.g. 100), wherein each unit cell depositsa single thin film material layer onto the coating surface. Thus thehead width (Wc) is ultimately a function of the desired total filmthickness being applied which is equal to the product of the thicknessapplied per unit cell and the number of unit cells. While thelongitudinal dimension (Lh) or coating width of the gas manifold (710)is generally fixed, the skilled artisan with readily recognize that aplurality of gas manifolds (710) can be joined together or individuallydisposed side by side along the (V) axis to increase the desired totalfilm thickness wherein each gas manifold (710) applies additional thinfilm layers to a substrate being transported thereunder. More generally,a single gas manifold (710) is configurable with the longitudinaldimension (L) and transverse dimension (Wd) of the precursor orificeplate (930) adapted to optimize the coating width and number of thinfilm layers being deposited per pass for a particular purpose. It isalso noted that substrates may be cycled through a plurality of passesunder the same gas manifold (710), e.g. by a reciprocating linear motionto achieve greater total material thicknesses. It is also noted that thecoating area of the gas distribution manifold can be matched to aparticular non-web substrate (e.g. a large television screen) forcoating the large non-web substrate using a reciprocating motion ofeither the gas distribution manifold or the substrate or both.

Example Precursor Orifice Plates

Referring now to FIG. 10, a schematic section view taken through asingle unit cell (1000) of a first embodiment of the gas orifice plate(930) illustrates a first gas orifice plate design and gas flowpatterns. While the entire gas orifice plate (930) may comprise a singleunit cell (1000), the gas orifice plate (930) is preferably configuredas a unitary plate that includes a plurality of unit cells (1000)disposed side by side and extending along its transverse dimension (Wd)along the velocity axis (V). As detailed above, each unit cell (1000)deposits a single ALD coating layer or thin film onto a coating surfacebeing transported past the unit cell. In FIG. 10, a substrate (1025) istransported past the unit cell (1000) along the velocity axis (V) and isspaced apart from a base surface of the unit cell by a separationdistance (1030), which may have a dimension between 0.5 and 5 mm with apreferred separation distance range of 0.5 to 2 mm. The substratecoating surface faces the unit cell (1000) and is preferably coplanarwith the unit cell base surface (1050). In a preferred embodiment theseparation distance (1030) is at least 0.5 mm to provide sufficientclearance between the base surface (1050) and the coating surface toaccommodate variation in the substrate thickness as well as anyundesirable fluctuations in the position of the substrate as it istransported past the gas manifold. Additionally the minimum separationdistance of 0.5 mm provides enough clearance between the bottom surface(1050) and the coating surface for gas exiting from the precursor andpurge nozzle assemblies to leak under the base surface (1050) to bedrawn into the exhaust inlets and removed from the region proximate tothe coating surface. The minimum separation distance of the presentinvention of 0.5 mm is much larger than the operating separationdistance of 0.025 mm disclosed in the prior art by Levy et al., which isnot practical for coating moving webs or for coating substratessupported on a moving web.

The unit cell (1000) includes two precursor nozzle assemblies (1005A,1005B), for directing precursors (A and B) onto the coating surface. Theunit cell includes two inert gas or purge nozzle assemblies (1015A,1015B) for directing an inert or purge gas, (e.g. nitrogen) onto thecoating surface, and each purge nozzle assembly is disposed between twoprecursor nozzle assemblies. The unit cell (1000) includes three exhaustinlets (1010A, 1010B, 1010C) each comprising a longitudinal slot (1060)that passes vertically through the precursor orifice plate (930). Eachexhaust inlet is in fluid communication with appropriate exhaust flowpassages that pass vertically through the flow distribution plate (925),the exhaust orifice plate (920) and the exhaust collection plate (915)to one of the exhaust collection manifolds (830) or (835). Each exhaustinlet (1010A, 1010B, 1010C) extends substantially over the entirelongitudinal dimension of the precursor orifice plate (930) andwithdraws gas from the separation distance (1030). Each exhaust inlet isdisposed between a precursor nozzle assembly (1005A, 1005B) and a purgenozzle assembly (1015). Note also that the precursor nozzle assembly(1005A) has an exhaust inlet and a purge nozzle assembly disposed to itsleft when another unit cell is placed adjacent to the unit cell (1000)on its left edge.

As the substrate coating surface advances past the unit cell (1000) itfirst passes the first precursor nozzle assembly (1005A) which directsprecursor A onto the coating surface. Precursor A reacts with thecoating surface changing the chemical and physical properties of thecoating surface and producing a reaction byproduct. Unreacted precursorA, reaction byproduct and inert gas expelled from the purge nozzleassembly (1015A) mix together in the separation distance (1030)proximate to precursor nozzle assembly (1005A) and the gas mixture ofunreacted precursor A, inert gas and reaction byproduct associated withthe reaction of precursor A with the coating surface is substantiallycompletely drawn into the first exhaust inlet (1010A) as the coatingsurface is advanced past the exhaust inlet (1010A). Additionally thecurtain of inert gas expelled by each purge nozzle assembly tends toprevent the unreacted precursor A and reaction byproduct for flowing ordiffusing parallel to the coating surface toward other precursor nozzleassemblies before it is drawn into the exhaust inlet (1010A). Note thatanother exhaust port, e.g. of an adjacent unit cell not shown, may bepositioned adjacent to the precursor nozzle assembly (1005A) opposed toexhaust inlet (1010A) such that two exhaust inlets surround theprecursor nozzle assembly (1005A) to continuously withdraw gases fromthe separation distance (1030).

The substrate coating surface then advances past the purge nozzleassembly (1015A) which directs inert gas onto the coating surface. Theinert gas flow provides an inert gas curtain extending along thelongitudinal axis (L) that segregates precursor A from precursor B inthe separation distance (1030), which is large enough to allow unreactedprecursor and reaction byproduct to be drawn into exhaust inlets butsmall enough that gas diffusion to neighboring precursor nozzleassemblies is prevented. In addition the inert gas flow from the purgenozzle assemblies (1015A) tends purge the coating surface as it passesunder the purge nozzle assemblies (1015A) and continues to purge theseparation distance (1030) of any additional unreacted precursor A andreaction byproduct. Meanwhile, gasses are continuously withdrawn fromthe coating surface and separation distance (1030) proximate to thepurge nozzle assembly (1015A) by each of the exhaust inlets (1010A) and(1010B).

The coating surface then advances past the second precursor nozzleassembly (1005B) which directs precursor B onto the coating surface.Precursor B reacts with the coating surface after it has been altered bythe reaction with precursor A, and the reaction between precursor B andthe coating surface deposits a new thin film layer onto the coatingsurface while also producing another reaction byproduct. Unreactedprecursor B, reaction byproduct from the reaction of precursor B withthe coating surface and inert gas expelled from the first and secondpurge nozzle assemblies (1015A, 1015B) mix together in the separationdistance (1030) proximate to the precursor nozzle assembly (1005B) andare drawn into the second and third exhaust inlets (1010B and 1010C).The coating surface finally advances past the second purge nozzleassembly (1015B) which directs inert gas onto the coating surface tosegregate precursor A from precursor B and push waste gas toward theexhaust inlet (1010C). Note that another exhaust inlet, e.g. of anadjacent unit cell not shown, may be positioned adjacent to the purgenozzle assembly (1015B) opposed to exhaust inlet (1010C) such that twoexhaust inlets surround the purge nozzle assembly (1015B) tocontinuously draw gases from the separation distance (1030). In additionthe inert gas flow from the purge nozzle assembly (1015A) further purgesthe coating surface as it passes the port (1015B) and continues to purgethe separation distance (1030) of any unreacted precursor B and reactionbyproduct.

Referring to FIG. 11, a second embodiment of a precursor orifice plate(930) includes a unit cell (1100). In this embodiment the unit cell(1100) has three separation distances. A first separation distance(1140) extends between bottom surfaces of each of the precursor nozzleassembly base walls (1160A) and (1160B) and the coating surface and thefirst separation distance (1140) may have a dimension in a range of 4-10mm. A second separation distance (1175) extends between bottom surfacesof each of the purge nozzle assembly base walls (1165) and the coatingsurface and the second separation distance may have a dimension in therange of 2-8 mm. A third separation distance (1145) extends between aprecursor orifice plate base surface (1150) and the coating surface andthe third separation distance may have a dimension in the range of 0.5to 3 mm. In a preferred embodiment the third separation distance (1145)is at least 0.5 mm to provide sufficient clearance between the basesurface (1150) and the coating surface to accommodate variation in thesubstrate thickness as well as any undesirable fluctuations in theposition of the substrate as it is transported past the base surface(1150). Additionally the minimum separation distance of 0.5 mm providesenough clearance between the bottom surface (1150) and the coatingsurface for gas exiting from the purge nozzle assemblies to leak underthe base surface (1150) for being drawn into the exhaust inlets andremoved from the region proximate to the coating surface.

Generally the second separation distance (1175) is larger than the thirdseparation distance (1145) and the first separation distance (1140) islarger than the second separation distance (1175); however in someembodiments the first and second separation distances (1140) and (1175)may be substantially equal with both being greater than the thirdseparation distance (1145). In this embodiment, the purge nozzleassemblies (1115A and 1115B) include a base wall (1165) with its bottomsurface defining the second separation distance (1175) and opposingparallel walls (1162) that extend vertically downward to meet the basesurface (1150). The walls (1162) separate the purge nozzle assemblies(1115A and 1115B) from adjacent exhaust inlets (1105A and 1105B) andconvey purge gas exiting from the purge gas nozzle assemblies toward thecoating surface while preventing the purge gas from being drawn into theadjacent exhaust inlets (1105A and 1105B) until it is proximate to thecoating surface, e.g. 0.5 to 2 mm from the coating surface. Moreover,the walls (1162) provide a mechanical barrier for helping to preventprecursor A expelled from the precursor nozzle assembly (1110) frommixing with precursor B expelled from the precursor nozzle assembly(1120). In this embodiment, each precursor nozzle assembly (1110) and(1120) includes a base wall (1160A and 1160B) with its bottom surfacedefining the third separation distance (1140). Each precursor nozzleassembly (1110) and (1120) is bounded by opposing side walls (1162)which help to covey precursor to the coating surface and prevent theprecursor from diffusing past the purge gas nozzle assemblies.

The unit cell (1100) includes a first precursor nozzle assembly (1110)for directing precursor A onto the coating surface (1130) and twoopposing exhaust inlets (1105A) disposed one on each side of the firstprecursor nozzle assembly (1110) for collecting exhaust gas from thecoating surface and from the volume bounded by each of the separationdistances (1140) and (1145). The exhaust gas collected by the twoexhaust inlets (1105A) includes unreacted precursor A, reactionbyproduct and inert gas. Similarly the unit cell (1100) includes asecond precursor nozzle assembly (1120) for directing precursor B ontothe coating surface (1130) and two opposing exhaust inlets (1105B)disposed one on each side of the second precursor nozzle assembly (1120)for collecting exhaust gas from the coating surface and from the volumebounded by each of the separation distances (1140) and (1145). Theexhaust gas collected by the two exhaust inlets (1105B) includesunreacted precursor B, reaction byproduct and inert gas. Each of thefour exhaust inlets (1105A and 1105B) pass through the precursor orificeplate (930) and are in fluid communication with flow channels passingthrough the flow distribution plate (925), the exhaust orifice plate(920) and the exhaust collection plate (915) which delivers waste gasinto one of the exhaust gas manifolds (830) or (835) and the blower(1485) withdraws outflow from each of the exhaust collection manifolds(830) and (835). According to one aspect of the present invention,exhaust gas collected by exhaust inlets (1105A) is segregated fromexhaust gas collected from exhaust inlets (1105B) such that only exhaustgas that includes unreacted precursor A exits from the exhaustcollection manifold (805) and only exhaust gas that includes unreactedprecursor B exit from the exhaust collection manifold (810).

The unit cell (1100) further includes a first purge nozzle assembly(1115A) disposed between the first precursor nozzle assembly (1110) andthe second precursor nozzle assembly (1120) and a second purge nozzleassembly (1115B). Each purge nozzle assembly (1115A, 1115B) directsinert gas onto the coating surface between opposing walls (1162) and theinert gas leaks under the walls (1162) through the third separationdistance (1145) to prevent precursor A from mixing with precursor B. Ina preferred embodiment the gas pressure and or gas volume expelled fromeach of the purge nozzle assemblies (1115A, 1115B) may be greater thanthe gas pressure and volume expelled from each of the precursor nozzleassemblies (1110, 1120) to ensure that precursor gas and or reactionbyproduct do not leak under the protruding walls (1162).

As the substrate (1130) advances past the unit cell (1100) it firstpasses the first precursor nozzle assembly (1110) which directsprecursor A onto the coating surface. Precursor A reacts with thecoating surface changing the chemical and physical properties of thecoating surface and produces a reaction byproduct. Unreacted precursorA, the reaction byproduct and inert gas expelled from the first purgenozzle assembly (1115A) mix together proximate to the coating surfaceand in the volumes defined by the separation dimensions (1145) and(1140). The mixture is withdrawn from the volumes defined by theseparation dimensions (1145) and (1140) and from the coating surface bythe two exhaust inlets (1105A) disposed one on each side of the firstprecursor nozzle assembly (1110). Each of the exhaust inlets (1105A)removes unreacted precursor A, reaction byproduct and inert gas withoutmixing unreacted precursor B with the exhaust gases. The substrate thenadvances past the purge nozzle assembly (1115A) which directs inert gasonto the coating surface to further purge any reaction byproduct orunreacted precursor A from the coating surface. As described above, theinert gas expelled onto the coating surface forms a gas curtain thatextends from the base wall (1165) to the coating surface and segregatesprecursor A from precursor B.

The substrate (1130) then advances past the second precursor nozzleassembly (1120) which directs precursor B onto the coating surface.Precursor B reacts with the coating surface after it has been altered bythe reaction with precursor A, and the reaction of precursor B with thechemically and physically altered coating surface deposits a thin solidfilm layer onto the coating surface while also producing anotherreaction byproduct. Unreacted precursor B, the reaction byproduct andinert gas expelled from purge nozzle assemblies (1115A and 1115B) mixtogether at the coating surface. The mixture is withdrawn from thevolume defined by the separation distances (1140 and 1145) and from thecoating surface by the exhaust inlets (1105B) disposed one on each sideof second precursor nozzle assembly (1120). The substrate then advancespast the purge nozzle assembly (1115B) which directs inert gas onto thecoating surface. The inert gas expelled onto the coating surface forms agas curtain that extends between the base walls (1165) and the coatingsurface and segregates precursor B from precursor A and further removesreaction byproducts and unreacted precursor B from the coating surface.

Precursor and Inert Gas Delivery

Referring to FIG. 12, the gas manifold (710) is shown partially cut awayin a top isometric split view which depicts hardware in a rear portionof the figure and gas flow in a front portion of the figure toillustrate precursor flow through the gas manifold (710). The flow pathof precursor A is patterned for clarity. FIG. 12 depicts a section viewtaken through the exhaust collection plate (915), the exhaust orificeplate (920) and the flow distribution plate (925). The precursor orificeplate (930) is not shown in FIG. 12. Precursor A enters the gas manifold(910) through a plurality of precursor ports (815). Precursor ports(815) pass through the exhaust collection plate (915) and deliverprecursor A into a first transverse fluid conduit formed in the exhaustorifice plate (920). Item (1236) comprises precursor A as it wouldappear passing through the first transverse conduit. Precursor A exitsthe transverse conduit via a plurality of longitudinal flow paths (1241)which are formed by a plurality of first longitudinal fluid conduitsformed in the flow distribution plate (925). Each of the plurality offlow paths (1241) feeds a first precursor nozzle assembly, such as(1005A or 1110) detailed above, and gas flow through a plurality offirst precursor nozzle assemblies is shown as (1250) in FIG. 12.

Precursor B enters the gas manifold (910) through a plurality precursorports (820). Precursor ports (820) pass through the exhaust collectionplate (915) and deliver precursor B into a second transverse fluidconduit formed in the exhaust orifice plate (920). Item (1235) comprisesprecursor B as it would appear passing through passing through thesecond transverse conduit formed in the exhaust orifice plate (920).Precursor B exits the second transverse conduit via a plurality ofsecond longitudinal flow paths (1240) which are formed by a plurality ofsecond longitudinal fluid conduits in the flow distribution plate (925).Each of the plurality of flow paths (1240) feeds a second precursornozzle assembly, such as (1005B or 1120) detailed above, and gas flowthrough a plurality of second precursor nozzle assemblies is shown as(1265) in FIG. 12.

As further shown in FIG. 12, inert gas enters into the manifold throughinert gas ports (825). The a plurality of inert gas ports pass throughthe exhaust collection plate (915) and deliver inert gas flow into athird transverse fluid conduit formed in the exhaust orifice plate(920). Item (1237) comprises inert gas as it would appear passingthrough the third transverse conduit formed in the exhaust orifice plate(920). Purge gas exits the third transverse conduit via a plurality ofthird longitudinal flow paths (1242) which are formed by a plurality ofthird longitudinal fluid conduits in the flow distribution plate (925).Each of the plurality of flow paths (1242) feeds a purge nozzleassembly, such as (1015A, 1015B or 1115A and 1115B) detailed above, andpurge gas flows through a plurality of purge nozzle assemblies extendinglongitudinally from each of the flow paths (1242).

Exhaust Gas Removal

Referring now to FIGS. 9 and 13, FIG. 9 is a section view taken throughsection (900-900) of FIG. 8 and FIG. 13 depicts an explodes view (1300)taken from FIG. 9. The exploded view (1300) depicts a unit cell.Referring to FIG. 9, from top to bottom shows a wall of an exhaustmanifold (835) which is shown attached to the exhaust collection plate(915) at its base. The exhaust collection plate (915) mates with theexhaust orifice plate (920), which mates with the flow distributionplate (925) and the flow distribution plate mates with the precursororifice plate (930). Each of the exhaust collection plate (915), theexhaust orifice plate (920), the flow distribution plate (925) and theprecursor orifice plate (930) is a substantially rectangular or squareplate shaped elements having opposing parallel surfaces separated by amaterial thickness and substantially equal longitudinal and transversedimensions. The longitudinal dimension corresponds with a width of thecoating surface (Ws) or a coating width of the gas distributionmanifold. The transverse dimension corresponds with width of the gasdistribution manifold (Wc) which is some multiple of width of a singleunit cell, (e.g. 100).

Each of the plates may be gas sealed with respect to its mating platessuch as by O-rings, gaskets, or the like, not shown, to prevent gas fromleaking out of the distribution manifold from between the plates. Eachplate also includes various orifices, channels or the like that extendthrough or partially through the plates and which serve as fluidconduits for conveying gases through the gas manifold as required.Additionally mating plates may include corresponding surface channels orthe like that are joined together when the plates are assembled to formfluid conduits. The plate materials may comprise metal allows, e.g.aluminum or stainless steel or the plates may comprise formable polymermaterials e.g. ABS or polycarbonate, or the plates may comprise ceramicmaterials such as quartz or glass.

Referring to FIG. 13, an example exhaust gas flow path is shown whereinthe precursor nozzle assembly (1340) is disposed between opposingexhaust inlets (1355A). As shown, each exhaust inlet (1355A) comprises alongitudinal slot that passes vertically entirely through the precursororifice plate (930) and entirely through the flow distribution plate(925) to the exhaust orifice plate (920). The exhaust orifice plate(920) includes opposing longitudinal slots (1310) and (1315) that extendfrom opposing faces of the exhaust orifice plate (920). The opposingslots terminate at a center wall (1305) which includes a plurality ofcircular orifices (1320) passing there through. The exhaust gas passesthrough each of the plurality of circular orifices (1320) and flows onto the exhaust collection manifold (835). The orifices (1320) are sizedto create a choked flow condition through the center wall (1305) suchthat gas flow from the longitudinal slot (1310) to the slot (1315) isrestricted by the orifices (1320). The restricted gas flow results indrawing a substantially uniform exhaust gas flow through each of theorifices (1320) along the longitudinal length of the center wall (1305).Similarly. the precursor nozzle assembly (1335) is disposed betweenopposing exhaust inlets (1355) which are substantially identical inconstruction and operation to the exhaust inlets (1355A) except that theexhaust inlets (1355) may deliver exhaust gasses collected thereby to analternate exhaust collection manifold (830).

A blower (1485) is in fluid communication with each of the exhaustcollection manifolds (830) and (835) and operation of the blower drawsexhaust gas out of each of the exhaust collection manifolds (830) and(835). The resulting pressure drop in each of the exhaust collectionmanifolds (830) and (835) uniformly draws exhaust gas volume througheach of the orifices (1320) which draws exhaust gas into each of theexhaust inlets (1355A). Similarly, the precursor nozzle assembly (1335)is disposed between opposing exhaust inlets (1355) which aresubstantially identical to the exhaust inlets (1355A) except that theexhaust inlets (1355) pass through each of the plurality of circularorifices (1325) and flows to the exhaust collection manifold (830)instead of the exhaust collection manifold (830).

Example Nozzle Assemblies

Referring now to FIGS. 10-13 each of the precursor nozzle assemblies(1005A, 1005B, 1110, 1120, 1335, 1340) and each of the purge nozzleassemblies (1015A, 1015B, 1115A, 1115B, 1350) comprises a longitudinalinput chamber (1330) that is bounded by a base wall (1045, 1160A, 1160B,1165, 1345) and by opposing side walls (1035, 1135, 1375). As bestviewed in FIG. 13, each of the longitudinal input chambers (1330) ispartially formed in the precursor orifice plate (930) and partiallyformed in the flow distribution plate (925). As best viewed in FIG. 12,each of longitudinal input chambers associated with a precursor nozzleassembly is fed precursor gas through one of the first and secondlongitudinal conduits (1240) or (1241) and each of the longitudinalinput chambers associated with a purge nozzle assembly is fed inert gasthrough one of the third longitudinal conduits (1242). Thus appropriategases enter and fill each of the longitudinal input chambers (1330) fromone end thereof. Each of the longitudinal input chambers (1330) extendshorizontally along the longitudinal dimension of the precursor orificeplate (930) substantially along the full longitudinal dimension (L) ofactive portion of the gas manifold and defines a coating width (Ws) of agas manifold.

Each of the base walls (1045, 1160A, 1160B, 1345) includes a pluralityof orifices (1070, 1170, 1370) that extend through the base wall alongan axis that is substantially normal to the coating surface. In apreferred embodiment each of the plurality of orifices (1070, 1170, and1370) is circular with a diameter that is small enough to cause chokedgas flow exiting from each of the longitudinal chambers (1330). Morespecifically choked gas flow results when gas flow out of thelongitudinal chambers (1330) is restricted by the circular orifices(1070, 1170, and 1370). The choked gas flow provides an advantage overthe prior art in that small cyclic variations in gas pressure and or gasvolume within any of the longitudinal input chambers (1330) does notresult in corresponding variations in gas volume passing through theorifices (1070, 1170, 1370). Additionally, the choked flow conditionleads to a substantially uniform gas volume passing through each of thecircular orifices along the full longitudinal length of the longitudinalinput chambers (1330). Thus the choked flow condition advantageouslyexposes the coating surface passing under each gas nozzle assembly to asubstantially uniform volume of process gas per unit time and per unitlength along the longitudinal axis (L) thereby leading to completesaturation over the system coating width (Ws) during the desired dwelltime. Thus the choked flow condition provided by the present inventionprovides improved coating uniformity at atmospheric pressure while alsoreducing precursor use. In the example embodiments described above gasorifices (1050, 1170, 1370) that provided the desired choked flowcondition comprise circular holes with diameters ranging from 0.025 to0.127 mm (0.0001 to 0.005 inches). Preferably orifice diameters rangefrom 0.064-0.0165 mm, (0.00025-0.00065 inches). In the exampleembodiments described above, the gas orifices are spaced apart withcenter to center or pitch dimension ranging from 0.25 to 10 mm (0.010 to0.4 inches) and preferably about 3 mm (0.12 inches). Other spacingarrangements that provide the desired uniform gas distribution along thelongitudinal axis are usable without deviating from the presentinvention. In further embodiments the plurality of circular aperturesmay be replaced by one or more longitudinal slots, one or more oval orother shaped orifices or other orifice patterns that provide the desireduniform gas distribution along the longitudinal axis without deviatingfrom the present invention.

Gas exiting from each of the gas orifices (1070, 1170, 1370) impingeswith normal incidents onto the coatings surface with a distributionpattern, which may have a circular diameter. The shape and size of thedistribution pattern is at least dependent on the gas density, theseparation distance, and other flow characteristics. As noted above, asa result of the choked flow condition the distribution pattern is lessdependent on the gas pressure inside the longitudinal input chambers(1330) or the mass flow rate of gas entering the longitudinal inputchambers and this improves coating characteristics. Preferably theorifices (1070, 1170, 1370) are uniformly spaced apart along thelongitudinal axis with a center to center pitch that provides someoverlap of the distribution pattern of adjacent orifices. The center tocenter spacing and diameter of the circular orifices (1070, 1170, 1370)is selected to uniformly distribute gas volume substantially along theentire longitudinal dimension (L) of the gas manifold (710) whichcorresponds to the active substrate coating width (Ws).

The size and shape of the orifices passing through bases walls of thepurge nozzle assemblies (1015A, 1015B, 1115A, 1115B, 1350) may bedifferent from the size and shape of orifices passing through base wallsof the precursor nozzle assemblies (1005A, 1005B, 1110, 1120, 1335,1340) in order to differentiate between the volume of purge gas and thevolume or precursor gas that is directed onto the coating surface. Thesize and shape of gas orifices passing through base walls of theprecursor nozzle assemblies (1005A, 1005B, 1110, 1120, 1335, 1340) maybe different for different precursor gasses in order to differentiatethe volume of one precursor with respect to another precursor that isdirected onto the coating surface. The center to center spacing or pitchof orifices passing through base walls may be varied from one nozzleassembly to another to differentiate gas volume delivery to the coatingsurface per unit length. For example precursor nozzle assemblies mayhave a larger or a smaller total number of orifices than purge nozzleassemblies or one precursor nozzle assembly may have a larger or asmaller total number of orifices than another precursor nozzle on thesame gas manifold. More generally, according to various embodiments ofthe present invention the size, shape and pitch of the orifices leadingout of the longitudinal input chambers (1330) may be varied in order toadjust gas distribution patterns at the coating surface to more reliablyobtain complete saturation at the coating surface. Additionally theseparation distances (1030, 1145, 1140 and 1175) may be varied in orderto adjust gas distribution patterns in order to more reliably obtaincomplete saturation at the coating surface.

Example Gas Flow at the Coating Surface

Referring to gas flow lines shown exiting from gas orifices in each ofFIGS. 10 and 11, in each of the unit cell embodiments described abovethe orifices passing through bases walls (1045, 1160A, 1160B, 1325) areoriented substantially along an axis that is normal to the coatingsurface, which may be a vertical axis. Gas exiting a circular gasorifice may form a substantially conical pattern defining a circularzone over which gas impinges into the coating surface. As describedabove, the diameter of the circular zone depends on the separationdistances (1030, 1140), the gas orifice diameter the gas pressure and tosome extend may depend on gas temperature, density, substrate velocityetc. After impinging on the coating surface, the gas is deflected awayfrom the coating surface in the same conical pattern which continues toexpand in diameter with increasing distance from the coating surface.Accordingly much of the deflected gas is directed toward the exhaustinlet e.g. (1010B, 1010C, 1105A) where it is quickly removed from theseparation distances (1030, 1140, and 1145).

To the extent that a portion of the deflected gas is directed parallelto or nearly parallel to the coating surface, the purge nozzleassemblies (1015A, 1115A, 1350) disposed on opposing sides of theprecursor nozzle assemblies deliver a curtain of inert gas into theseparation distances (1030, 1145) and the curtain of inert gas tends toprevent precursor gas from flowing or diffusing parallel to the coatingsurface and preferably confines the precursor to a low pressure areagenerated by the exhaust inlets (1010A, 1105A) which remove unreactedprecursor gas and reaction byproducts from the separation distances(1030, 1140). In some embodiments, it may be preferable to deliver ahigher volume of inert gas through the purge nozzle assemblies (1015A,1115A) in order to prevent precursor from flowing parallel to or nearlyparallel to the coating surface. Thus in addition to precursor gas beingdrawn into the exhaust inlets e.g. (1010A, 1105A) it is desirable that aportion of the inert gas expelled from the purge nozzle assemblies(1015A, 1015B, 1115A, 1115B) and deflected from the coating surfaceflows through the separation distance (1030) and (1145) toward theadjacent exhaust inlets (1010A) and (1105A).

In each of the unit cell embodiments described above, purge nozzleassemblies are disposed between precursor nozzle assemblies to preventdissimilar precursors from mixing in the separation distances betweenthe gas precursor orifice plate (930) and the coating surface. In eachof the unit cell embodiments described above the separation distances(1030, 1145) are selected to guide unreacted precursor gas and reactionbyproducts deflected from the coating surface toward the exhaust inlets(1010) and (1105) to prevent the mixing of dissimilar precursors and topromote rapid and complete reactions between the precursors and thecoating surface over the entire coating surface area.

Gas Control System

Referring now to FIG. 14, a gas control system (1400) according to oneembodiment of the present invention is shown schematically. The gascontrol system (1400) includes a gas manifold (1460), such as the gasmanifold (710) shown in FIG. 8 and described above. Precursors and inertgas are delivered into the gas manifold (1460) via input lines (1412)e.g. over a plurality of input conduits. The input lines (1412) mayinclude one or more pressure gauges (P), flow meters (1425, 1455)control valves (1435, 1440, 1445) and pressure regulators (1410) and(1420) to regulate gas input pressure and mass flow rate and to modulateprecursor input as required. Inert gas is delivered from an inert gassupply (1405) which is pressure regulated by a gas pressure regulator(1410).

The gas control system (1400) further includes a blower (1485) drawingexhaust gas through the manifold (1460). The exhaust gas may bewithdrawn through two separate exhaust lines (1465) and (1470) with onegas line (1465) associated with exhaust gas that includes unreactedprecursor A and the other gas line (1470) associated with unreactedprecursor B respectively. An exhaust gas collection module (1475) isdisposed between the blower (1485) and the manifold (1460) forcollecting and processing exhaust gas. The exhaust collection module(1475) may comprise a trap for trapping unreacted precursors, aprecursor reclaiming module for reclaiming unreacted precursors or both.The exhaust collection module (1475) may also include traps or filteringdevices for separating the reaction byproduct from the exhaust gases.The gas control system (1400) may also include a throttle valve (1480)or the like disposed between the gas manifold (1460) and the blower(1485) suitable for adjusting exhaust gas pressure and or mass flowrate.

The gas control system (1400) may include one or more conventional gasbubblers (1450) to vaporize liquid or solid precursors. Alternately oradditionally, the system may include one or more gaseous precursorcontainers that do not require a bubbler. The gas bubbler (1450)contains liquid or solid precursor in a sealed container and inert gasis delivered into the container along flow line (1430). Inert gas inputto the bubbler (1450) may be regulated by a pressure regulator (1410)and a mass flow controller (1425). Precursor vapor is released from thebubbler through a control valve (1440). Control valves (1435, 1440, and1445) may be used to prevent inert gas from flowing into the bubbler(1450) and or to prevent precursor from exiting from the bubble.

Gas controller (1400) delivers inert gas directly to the gas manifold(1460) e.g. into each of the inert gas input ports (825) shown in FIG.8. Additionally inert gas may be mixed with one or both precursors as acarrier gas such that a mixture or inert gas and precursor vapor aredelivered into each of the precursor input ports (815), (820) shown inFIG. 8.

While the present embodiments use a binary precursor system, theinvention is not limited to two precursors. The invention is open to anynumber of precursors necessary to achieve the desired coating goalswithout deviating from the present invention. Moreover the gas controlsystem (1400) is a schematic representation and may include a pluralityof different precursor and inert gas containers, bubblers and flow pathsas may be required for a user to configure the gas manifold to apply avariety of different material layers onto a plurality of differentsubstrates.

Deposition Systems Including Substrate Transport Systems

FIGS. 15 and 16 respectively illustrate deposition systems includingdifferent substrate transport systems according to embodiments of thepresent invention.

Referring to FIG. 15, deposition system (1500) includes a substratetransport system that is designed to transport the substrate in asubstantially planar configuration beneath a gas deposition head systemto deposit a coating on the substrate according to techniques describedabove. The deposition head system is designed and arranged such that theseparation distance between each unit cell and the coating surface ofthe substrate is substantially the same when the substrate passesbeneath the head system. The embodiment of FIG. 15 utilizes the gasdeposition head system shown in FIG. 3 which includes four unit cells(1510, 1520, 1530, 1540).

In the embodiment of FIG. 15, the transport system includes a supplyroll (1550), which supplies the uncoated substrate, and a take-up roll(1560) on which the coated substrate is collected. During the depositionprocess, the supply roll (1550) rotates, for example in a counterclock-wise direction, to unwind the substrate. In some embodiments andas shown, the substrate may be transported over an optional substratesupport (1570) which, when present, can assist in maintaining thesubstrate in a substantially planar configuration. As the substratepasses beneath the gas deposition head system, a layer is deposited onthe coating surface according to techniques described above. In thisembodiment, a drive mechanism (1580) rotates the take-up roll (1560) tocollect the coated substrate which, in turn, causes the supply roll(1550) to rotate to supply the substrate. However, in other embodiments,a drive mechanism may be associated with supply roll (1550) instead of,or in addition to, the drive mechanism associated with the take-up roll(1560). In addition, the transport system (1500) includes a gas supplymodule (1585) for delivering precursor and inert gas to correspondinggas nozzle assemblies of each of the unit cells and an exhaust module(1590) for collecting exhaust gas through exhaust channels of the unitcells. In a preferred embodiment, the substrate is advanced past the gasdeposition head at an approximately velocity of 24 m/min, each of thegas nozzle assemblies has an approximate nozzle width of 1 mm and theseparation distance between the coating surface and a base surface ofthe deposition head is approximately 0.5 mm. In the example embodimentof FIG. 15 four unit cells are shown with each unit cell depositing asingle solid film layer onto the coating surface by an ALD coatingprocess. In other embodiments, the system (1500) may be configured todeposit more solid film layers by increasing the number of unit cells ofthe deposition head system.

Referring to FIG. 16, deposition system (1600) includes a substratetransport system that is designed to transport the substrate in a curvedconfiguration to deposit a coating on the substrate according totechniques described above. In this embodiment, the deposition head isalso curved such that the separation distance between each unit cell(1610, 1620, 1630, 1640) and the coating surface is substantially thesame when the substrate passes beneath the head. Similar to theembodiment of FIG. 15, the transport system includes a supply roll(1650), which supplies the uncoated substrate, and a take-up roll (1660)which collects the coated substrate. The transport system includes acurved substrate support element (1670) for maintaining the substratecoating surface equidistant from each of the unit cells (1610, 1620,1630, 1640). A drive mechanism (1680) rotates the take-up roll (1660) tocollect the substrate which, in turn, causes the supply roll (1650) torotate to supply the substrate. However, in other embodiments, thecurved substrate support element (1670) may comprise a roller driven bythe a drive mechanism (1680) to advance the coating surface past theunit cells at the desired velocity. Additionally the drive mechanism(1680 may include elements for driving the supply roll (1610).

In all of the above described embodiments, inert gas as well asprecursor gas is substantially continuously delivered into the gasmanifold (710) through one or more inert gas input ports (825) orthrough at least one precursor input port (815) and (820) associatedwith each precursor being used in the coating process. In all of theabove embodiments, exhaust gas is substantially continuously removedfrom the gas manifold (710) through each of a plurality of exit ports(805) and (810). In other embodiments a single exhaust exit port isusable. The exit ports (805) and (810) withdraw gas from the triangularshaped exit plenums (830, 835). In other embodiments a single exitplenum is usable. Each exit plenum mates with an exhaust collectionplate (915) and the interface between each exit plenum and the exhaustcollection plate is sealed by gaskets, O-rings or the like. In addition,the mass flow rate pressure and temperature of each of the precursors aswell as the inert gas may be varied by control systems as needed toachieve complete saturation for a given coating cycle. In otherembodiments of the present invention a user may choose to deliver asingle precursor gas onto a substrate coating surface, e.g. to promotevapor phase deposition of self-assembled monolayers on the coatingsurface. In such cases, a single precursor gas may be delivered onto oneor all of the input ports (815, 820).

It will also be recognized by those skilled in the art that, while theinvention has been described above in terms of preferred embodiments, itis not limited thereto. Various features and aspects of the abovedescribed invention may be used individually or jointly. Further,although the invention has been described in the context of itsimplementation in a particular environment, and for particularapplications (e.g. ALD), those skilled in the art will recognize thatits usefulness is not limited thereto and that the present invention canbe beneficially utilized in any number of environments andimplementations in deposition methods such as chemical vapor deposition,physical vapor deposition, plasma etched chemical vapor deposition, andpulsed laser deposition. Accordingly, the claims set forth below shouldbe construed in view of the full breadth and spirit of the invention asdisclosed herein.

What is claimed is:
 1. A deposition head comprising: a number of parallel vertical walls defining successive parallel channels therebetween, each of the parallel vertical walls having a bottom surface, the bottom surfaces being coplanar and defining a base surface, every alternate channel of the successive parallel channels being an inert gas channel, the remaining channels of the successive parallel channels being precursor channels, wherein each of the parallel channels is characterized by a same length; a base wall disposed within every inert gas channel, each base wall spanning a width between the opposing parallel vertical walls defining that inert gas channel, each base wall including an inert gas orifice disposed therethrough, and each base wall being disposed part way along the length of that inert gas channel such that the base wall is recessed from the base surface by a first separation distance that is less than the length of the parallel channels; a plurality of first precursor nozzle assemblies each recessed from the base surface by a second separation distance, the plurality of first precursor nozzle assemblies being disposed within a first half of the precursor channels; a plurality of second precursor nozzle assemblies each recessed from the base surface by a third separation distance, the plurality of second precursor nozzle assemblies being disposed within a second half of the precursor channels such that the first and second precursor nozzle assemblies are interleaved.
 2. The deposition head of claim 1 further comprising a plurality of first exhaust channels disposed between the first precursor nozzle assemblies and the two opposing parallel vertical walls on either side thereof, and a plurality of second exhaust channels disposed between the second precursor nozzle assemblies and the two opposing parallel vertical walls on either side thereof.
 3. The deposition head of claim 2 further comprising a first precursor delivery system for delivering a first precursor to each of the plurality of first precursor nozzle assemblies; a second precursor delivery system for delivering a second precursor to each of the plurality of second precursor nozzles; an inert gas delivery system for delivering inert gas to each of the inert gas channels.
 4. The deposition head of claim 3 further comprising an exhaust gas removal system for drawing exhaust gas through each of the first exhaust channels and each of the second exhaust channels.
 5. The deposition head of claim 4, wherein the exhaust gas removal system keeps separate the exhaust gas drawn from the first exhaust channels from the exhaust gas drawn from the second exhaust channels.
 6. The deposition head of claim 1 wherein the first precursor nozzle assemblies each include circular orifices, each orifice having a same diameter, the diameter being in a range from 0.0165 to 0.127 mm.
 7. The deposition head of claim 6 wherein the diameter is in a range from 0.025 to 0.064 mm.
 8. The deposition head of claim 6 wherein the orifices are spaced apart with a center to center distance of 0.25 to 10 mm.
 9. The deposition head of claim 8 wherein the center to center distance is about 3 mm.
 10. The deposition head unit cell of claim 1 wherein the first separation distance is in the range of 8 mm to 2 mm.
 11. The deposition head of claim 1 wherein the second separation distance is in the range of 9.5 mm to 1 mm.
 12. The deposition head of claim 1 wherein the first and second separation distances are the same.
 13. A deposition head unit cell comprising: five parallel walls, each of the walls having a bottom surface, the five bottom surfaces being coplanar and defining a base surface; a first precursor deposition channel defined between the first and second of the five parallel walls; a first purge channel defined between the second and third of the five parallel walls; a second precursor deposition channel defined between the third and fourth of the five parallel walls; a second purge channel defined between the fourth and fifth of the five parallel walls; a first precursor nozzle assembly disposed within the first precursor deposition channel and a second precursor nozzle assembly disposed within the second precursor deposition channel, each precursor nozzle assembly having two parallel side walls defining a gas flow channel therebetween and disposed parallel to the five parallel walls, and an orifice plate disposed between the two parallel side walls, a bottom surface of the orifice plate defining a plane parallel to a base plane and recessed therefrom by a first separation distance, the orifice plate having a number of orifices defined therethrough; a first base wall disposed within the first purge channel and a second base wall disposed within the second purge channel, each base wall including a plurality of apertures disposed therethrough, each base wall having a bottom surface defining a plane parallel to the base plane and recessed therefrom by a second separation distance; and a first exhaust channel defined between the first nozzle assembly and the first of the five parallel walls, a second exhaust channel defined between the first nozzle assembly and the second of the five parallel walls, a third exhaust channel defined between the second nozzle assembly and the third of the five parallel walls, and a fourth exhaust channel defined between the second nozzle assembly and the fourth of the five parallel walls.
 14. The deposition head unit cell of claim 13 wherein the first separation distance is in the range of 9.5 mm to 1 mm.
 15. The deposition head unit cell of claim 13 wherein the second separation distance is in the range of 8 mm to 2 mm. 